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Back to the tanks - on what to bet on?
A 30 ton tank with something better than a 2 pdr should be feasible; the Matilda II was at 27 tons. The lighter tanks might be needed to overcome the budget restraints, though, while using the commercial engines (1x150 or 2x85/95 HP), so we can have enough of decent tanks. The Liberty must be kept at 340 HP, without attempts to increase the power, in order to give good service?
Best service for the Liberty engine is to attach long chains to them and use them as boat anchors
The WW I aircraft engines were made by a number of companies and while a good Liberty engine by a good maker was a decent enough engine, too many of them were junk from the day they left the factory door.
For a brief review : Liberty Notes
Why somebody thought that an engine with a 75 hour overhaul life would make a good tank engine I have no answer for.
The fact that few, if any, commercial operators (not counting rum runners) used the engine for very long, even getting them at surplus prices should have been another clue.
The engines used were not Libertys as built originally but a reworked engine developed and built by the Nuffield organisation (Morris Motors). The Nuffield engine wasnt actually too bad by the standards of 1940 it was the ancillaries like transmission, cooling and filtration that let it down. Nuffield Libertys with modified ancillaries carried on in service till 1945 so they cant have been too bad. Some Crusader gun tractors were modified by the Argentinians into SP guns and served until the mid 50s
Since the Germans were fond to mount anything or anything, here is what they used the Bren Carrier for (with 20mm Flak, 25mm ATG, 37mm ATG, 2pdr, 47mm ATG (whose in original?), French 75mm):
View attachment 276259
It still wasn't a good engine to work from.
View attachment 276260
Each Cylinder has it's own water jacket (welded sheet metal) which is almost a recipe for coolant leaks ( guess what? they leaked). The crankshaft Unless Nuffield changed it, had NO counterbalances and suffered from torsional vibration and broken crankshafts. Please note valve gear hanging out in the open, Common enough in WW I for air cooling of the valve gear but not really what you want in a tank. Nuffield may have thrown a sheet metal box around the valve gear later.
I can also tell you some stories about 1950s fire trucks I was driving in the 1970s, Desn't mean they were any good, just that department had no money to replace them ( to be fair a couple of them were spares and only got driven a couple hundred miles a year, being "in service" can have a lot of meanings).
Maybe by the standards of bolting a couple of bus engines together it wasn't too bad but that isn't exactly a good recommendation.Not saying it was a great engine just that by the standards of 1940 it wasnt too bad and all the reports I have read say that it was what was bolted onto the engine that caused most of the problems. Nuffield would have been better off building a land based Kestrel in my opinion but I dont know if that was ever considered. The Kestrel tank engine could have powered Britains tanks from 1940 to the Comet when the Meteor could be dropped in.
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Edgar Brandt (of mortar fame) was working on sub-caliber projectiles before WW II. ...
The sub caliber round may very well be superior at close ranges, where is the cross over point?
Do you want to poke a 40mm hole in the enemy tank or a 75mm hole? Just because you made a hole in the armor does NOT mean you destroyed what was behind the armor. Crew, ammo, engine, etc.
Don't forget the larger round will penetrate more armor at the SAME velocity as the smaller round due to having more weight/mass per unit ( sq in/sq cm) of frontal area.
Uh, Tomo. Above 15 ton I tank engine in front.
Problem with 15-25 ton I tanks is that they are small as in almost tiny.
65mm armor (2.5in) weighs 100lbs per sq ft. you don't get a lot of sq ft to the ton so light I tanks are tiny.
And even the T19 was smaller than what was wanted.
They commonly towed ammo trailers.
The British and Americans very seldom used old tank chassis for SP guns, new manufactured obsolete chassis yes.
The British could have done themselves a world of good by dumping the Covenanter in the rubbish bin early on and building tanks they could actually use.
1771 tanks of which only a handful were ever used in action at that was to carry bridges.
'My' I tank, with 6-cyl engine compartment aside the driver, should allow more space for combat compartment if the tank is overall as long as Valentine. Compared to the Archer, it should be able to fire during the advancement phase, in support of attacking tanks and infantry, not just to use it for ambushes.
You are confusing two different roles.
Using direct fire "able to fire during the advancement phase, in support of attacking tanks and infantry" and being a self-propelled artillery piece.
BTW, it appears from trying to measure scale drawings that the Valentine hull was only about 5 ft wide, about the same width as the light tanks and around 1/2 ft narrower than the early cruisers and a 1 1/2ft narrower than a Cromwell (Cromwell then sucks up some of the space with the Christie suspension). Grants and Shermans were actually rather narrow between the tracks but then so much of the tank was above the tracks.